Problem: Solve for $p$ : $-3 + p = 17$
Explanation: Add $3$ to both sides: $ \begin{eqnarray} \\ -3 + p &=& 17 \\ \\ {+3} && {+3} \end{eqnarray} $ $ \begin{eqnarray} \hphantom{-3 + p} &\hphantom{=}& \hphantom{17} \\ p &=& 17 {+ 3} \\ \end{eqnarray} $ Simplify. $ p = 20$